This invention relates to a fastener device.
Fastener devices comprising a threaded member for receiving a nut are well known. Such fastener devices are widely used in many applications ranging, for example, from retaining wheels in position on motor vehicles and aircraft to retaining steel girders in position in buildings. There is often a problem with the known fastener devices in that the nuts tend to work loose, for example due to the effects of vibration.
It is an aim of the present invention to obviate or reduce the above mentioned problem.
Accordingly, the present invention provides a fastener device comprising a nut, a threaded member for receiving the nut, and visual indicator means for visually indicating if the nut has unintentionally become loose on the threaded member during use of the fastener device, the visual indicator means being such that it comprises an indicator member which is pivotally mounted on the nut, at least one recess in the threaded member, and biasing means which biases the indicator member into the recess and thereby to an indicating position in which the indicator member gives a visual indication that the nut has become loose, the biasing means being such that it firstly operates automatically consequent upon the nut becoming unintentionally loose and it secondly operates without a requirement for a tool for tightening, and loosening the nut to be placed over the nut, and the indicator member being such that when it is in the recess it prevents further unintentional loosening of the nut on the threaded member.
The visual indicator means provides a simple means of indicating if a nut has become loose. The nut can then be tightened as necessary.
The indicator member may include an indicator portion which extends proud of the nut when the indicator member is in the recess.
The fastener device may include a pivot member which pivotally mounts the indicator member on the nut such that the indicator member extends radially with respect to a threaded bore through the nut. Preferably, the pivot member pivotally mounts the indicator member in a slot in the nut.
The recess for receiving the indicator member is preferably a slot on the threaded member. Other types of recess may however be employed.
The fastener device may be one in which there are at least two of the recesses for receiving the indicator member. As many of the recesses as desired may be employed.
The fastener device may be one in which there is only one of the indicator members on the nut. Alternatively, the fastener device may be one in which there are at least two of the indicator members on the nut. Generally, as many of the indicator members may be employed as is required to achieve a required degree of visual awareness and/or safety.
The biasing means may be a coil spring. Alternatively, the biasing means may be a V-spring. Other types of biasing means may be employed.
Advantageously, at least a part of the indicator member is coloured so as to attract attention. The indicator member may thus be provided with a non-fluorescent colour or a fluorescent colour. More than one colour may be employed if desired. Where a colour is employed, then it is preferably employed on at least sides of the indicator member.
The visual indicator means may be made of a plastics material. Any suitable and appropriate plastics material may be employed, for example nylon. Materials other than plastics materials may be employed if desired.
The threaded member will usually be a bolt or a stud. The threaded member will usually be made of a metal but other materials including plastics materials may be employed.
The fastener device of the present invention may be used for retaining wheels in position on vehicles such for example as cars, vans, lorries, coaches and buses. The fastener device may also be used as a central fastener device for retaining wheels in position in racing vehicles. The fastener device may alternatively be used as part of scaffolding clamps, especially where vibration is likely to cause loosening of the clamps. The fastener device may still further be used in the construction industry for bolting girders together, or in the aircraft industry for retaining components together.